“The company is working closely" with ABP to "determine the full facts as we await the results of the further tests,” Greencore said in a statement. Greencore plc chief executive Patrick Coveney is the brother of Minister for Agriculture Simon Coveney.

British supermarket chain Asda has also withdrawn three other Greencore products “as a precautionary measure” and “none of which contain equine DNA” Greencore said.

An ABP spokesman said “in the last few weeks we have carried out hundreds of tests on fresh beef and to date they have all tested negative for equine DNA.

“ABP again reiterates that we have never knowingly purchased or processed equine meat.”

Earlier today a French investigation into how horsemeat found its way into ready meals in Europe found that a French processing company called Spanghero sold as beef what could have been horsemeat.

"It would seem that the first agent in this chain to label the meat 'beef' was indeed Spanghero," France's consumer affairs minister Benoit Hamon told a news conference of the company based in the southwestern town of Castelnaudry.

"The investigation shows Spanghero knew the meat labelled as beef could be horse. There was a strong suspicion," he said, arguing that Spanghero could also not have failed to notice that the meat in question was much cheaper than beef.

Spanghero has rejected accusations that it knowingly sold horsemeat labelled as beef and said it believed that it was selling was beef.

"Spanghero confirms having placed an order for beef, having been led to believe it received beef, and having sold back what it thought was beef, properly labelled as such, in line with European and French regulations," the firm said in an emailed statement.

French agriculture minister Stephane Le Foll said the government was considering withdrawing Spanghero's operating licence.

The investigation found the company had generated a profit of €550,000 over six months by selling cheap horsemeat as beef, Mr Hamon said.

Meanwhile in the UK, three men were arrested tonight by officers investigating the horse meat scandal.

The men were arrested at plants in Aberystwyth and Todmorden, West Yorkshire, which were inspected on Tuesday by the Food Standards Agency.

“At Farmbox Meats near Aberystwyth, Dyfed-Powys Police have arrested two men aged 64 years and 42 years, and in a simultaneous operation police arrested a man aged 63 at the Peter Boddy Slaughterhouse in Todmorden, West Yorkshire," police said. Police said all have been arrested on suspicion of offences under the fraud act.

The two plants became the first UK suppliers suspected of passing off horse meat for beef.

Production at both plants was suspended pending the outcome of investigations into claims they supplied and used horse carcasses in meat products purporting to be beef for burgers and kebabs.

The FSA said today it had “detained” all meat found at the premises and seized paperwork and customer lists from the two companies.

The arrests came as it emerged a significant amount of horse meat containing the painkiller phenylbutazone, or “bute”, could have been entering the food chain for some time.

Authorities in Britain and France are trying to trace the carcasses of six horses contaminated with bute, which were slaughtered in a UK abattoir and may have entered the human food chain across the Channel.

The drug, which is potentially harmful to human health, was detected in eight horses out of 206 tested by the FSA in the first week of this month.

Two were intercepted and destroyed before leaving the slaughterhouse but the other six were sent to France, where horse meat is commonly eaten.

This morning the Food Safety Authority of Ireland said some batches of beef burger products from Rangeland Foods in Monaghan have been found to contain between five and 30 per cent horse meat.

The factory suspended production early last week after horse meat was found in a consignment of Polish beef product at the plant but after tests were conducted it was given the all-clear to resume production last Friday morning.

The authority said it had been notified by Rangeland Foods that it was withdrawing some batches of burger products which contained beef supplied from Poland that it produced for the catering and wholesale sectors.

“These products were sold to the catering and wholesale sectors and have been distributed to Ireland, the UK, Spain, France, Germany and the Netherlands,” an FSAI statement said.

“Rangeland Foods has confirmed to the FSAI that it has notified its suppliers that would have received these implicated products and a withdrawal is taking place. As is the protocol in food withdrawals, if these suppliers have subsequently traded these products onwards to other food businesses, they are compelled to notify them to ensure that a swift withdrawal is undertaken across the market.”

The authority said it was issuing a food alert for Ireland and would notify the European Commission via the rapid alert system for food and feed about the exported product. “The FSAI will continue to work with Rangeland Foods to ensure that all implicated product is removed from the market,” it said.

Restaurant chain Supermac’s has today said its burgers are not affected by the withdrawal. Rangeland Foods has supplied Supermac’s with burgers for more than 30 years.

"The issue which has arisen today bears absolutely no relevance to Supermac's meat products which are 100 per cent Irish,” chief executive Pat McDonagh said in a statement.

All beef in the chain’s burgers are “100 per cent Irish, fully traceable back to the farm and DNA tested to prove that it is 100% Irish beef.,” he said.

Mr McDonagh said the supplier gave a written guarantee and test results to show that products supplied to the fast food chain was 100 per cent Irish beef. Supermac’s has also carried out its own independent testing on the products and would continue to do so, he said.

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